Brush lifting device



c. RHNGWALD 1,933,760

BRUSH LIFTING DEVICE Filed Dec. l5. 1930 2 Sheets-Sheet l Novn "if,1937.

i, .Rf

Patented Nov. 7, 1933 f UNI-TED STATES BRUSH LIFTING DEVICE` ClarenceRingwald, Springfield, Ohio, assigner to Robbins & Myers, Inc.,Springeldhio, acorporation of Ohio Application December 15, 1930 SerialNo. 502,339

2o claims. (011724-279) f My invention relates to` electric motors ofthe brush lifting type and a novel brush lifting mechanism therefor.

Brush lifting'and shortcircuiting mechanisms y for motors starting as.repulsion motors and thereafter operating as induction motors are known.The brush lifting mechanism of my invention is disposedl wholly at theccmmutator end of the motor and hence rods, or other oper# ating devicesextending through the armaturel lare not required. Y

In accordance With my invention the brush lifting and short circuitingmechanism is a comtherebysupported and guided.

Such position. as will secure? rotation in either direction. A mechanismof thispclass requires a non-rotating guide for holding the brushcarrier in proper position relativetothe commutator `during-starting andto guide it back out of the way when the brushes are lifted andthe`short circuiting mechanism operated.

` According to my invention the guiding `mechanism `comprises a plateadjustably secured to the end frame of the motor, Withtwo pins extendingparallel to the axis of the shaft and extending into sleevesforming apart of the brush carrier frame, which brush carrier frame 'is Ildispose the centrifugal mechanism directly` uponrthe shaft and radiallyinside the guiding pins.

The centrifugal mechanism comprises a pair of Weights adapted to bethrown out by centrifugal force against the tension of-a pair'of springsupon the attainment of. a predetermined speed which'is considerablyhigher than the speed at whichv the weights will again be re-Y tracted.

The `brushes are applied to the commutator through the action of thesprings `which govern the centrifugal Weights. Theentire brush frame andbrushes have no bias, i. e., nojspring loading of their own andhence-'there is required no end bearing under constant Wear.

The frame of the centrifugal mechanism is a generally rectangularstamping which is light and inexpensive. Likewise, the centrifugalWeights and arms are simple-stampings. The springs are iight coilsprings placed in tension. These springs are light and strong andreadily replaceable. The entire mechanism is unusually compact,linexpensive and highly effective. It isreadily accessible forinspection. Y

Now in order to acquaint those skilled 'inthe art with the manner ofconstructing and operat- `9 of the laminations 1. These concentriccylin- 'J described hereinafter.

ing any excess lubricant tothe pocket 20 through ing a device embodyingmy invention'I shall describe, in connection With the accompanyingdrawings, a specific embodiment of the same.

In the drawings:` n y Figure 1 is a side elevation, partly in section,of a motor embodying my invention;

Figure 2 is a fragmentary section taken on the line 2-2of Figure 3,through thevbrush lifting device and commutator;

Figure 3k is a cross sectional view taken onthe line 3-3 of Figure 2;

Figure 4 is a side elevational View; of the inertia or centrifugalmechanism; 5

Figure 5 is an end view of the same, taken from the right of Figure 4;and i 77,0

4Figure 6 is a fragmentary view, illustratingY the connection.l of thespring to theinertia lever. Referring first to Figure 1, the motorherein showncomprises the eld laminaticns 1 and armature laminations 2,of known form, these'75` parts in an A. C. motor being generally termedstator and rotor, respectively. The stator laminations are connedbetween a flange 3, formed on one end of the cylindrical tubing shell 4and a filler sleeve 5, which is held in place by anging the opposite endof the sleeve 4, asindicated at 6. The opposite ends of the sleeve 4 arefinishedof as indicated at 7 8, to provide surfaces which are concentricwtih the inner face drical surfaces 7 and 8 are adapted to receive therims oiflanges 10 and 12 Yof the end frames or housings 13 and 14.Theseend frames 13a-,.14 support bearings 15 and 16, having suitablebushings 17 and 18 of anti-friction metal'cooperating with roundcylindrical bearing portions of the motor shaft 19. 4The bearing boxes15and 16 embody suitable oil pockets such as that shown -at20 at the leftof Figure 1. Oiler rings 22 dip` into the lubricant in the pocket 20vand ride upon the bearing portion such as 23 through a slot in theanti-friction sleeve 17, as indicated at 24. The outer end of thejournal boxjs .closedby a metal cap 25 pressed in place toexclude dustand to assist in draining the` lubri- 00. cating medium back to thepocket20 as through the passageway 26. Atv the opposite end ofthejournal box v15 a similari-flanged pressed yring 27, which isadapted toretain a feltwasher, if soV desired, prevents the entry of dust into thebear# ing vfrom the inner end andthe felt Washer (not shown) fitsclosely about the collar 28 `yvhich:,is mounted upon the shaft as willbe more l-fully It also assists in returnof the commutator supportingframe 47.

the extremeouter ends of the p'ns'Q-areriveted `overas indicatedat 86 sothat the saidguide pins 79 are rigidly connected tothe --plate 36.

The offset ears 84'prevent the riveted ends 86 from engaging the endplate 35. .Bolts, pro.- vided ,with suitable exterior fclamping nuts 89lextend throughfthe slots l82--82 and serve to clamp the main atbodyportion of the-platef36 against theend plate 35. Suitable indicia, forexample, notches r90-90 are marked upon the `plate .36, these-notchesbeing adapted to register with cooperating-marks on the plate 35. v i

The-slots 82`82 areV so arranged `that the rocker plate 36 may beshifted to sufficient angles to cause lthe motor to start v'invonedirection or the other, as desired; f

The shifter sleeve 67 is` adapted to be shifted -from the position shownin Figures 1 !and'2 when the Apartsare at rest, towards the right whenthemotor isbrought to substantiallysynchronous speed, throughtheoperation of asuitable centrifugal mechanism 92 which is shown lmore indetail in Figures 4, 5 and 6. The sleeve -either round in sectionoroblong in section,

having the ends of the vcoils substantially'paral- Y portions 95-95 ofrelatively limited area `but of considerable resiliency, whereby theyare adapted to bridge the insulating plate 60 which liesbetween thecommutator bars and the body At itsy oppositeend the shifter sleeve 67is 'provided ,with a pair of parallel transverse .grooves -96-96 forreceiving the shifter pins 97 which lie parallel to earch otheronopposite sides of the shaft 19.y Y

The inertia, or `centrifugal mechanism is adapted to swing the pins 97.aboutthe pin- ;left, as viewed in Figures 1 and 2.

1 brushi holder frame.

tles or pivots 98 to shift the sleeve 67 to the The connection betweenthe shifter sleeve and the brush holder frame'is provided by formingashoulder 99 upon the left handend ofthe sleeve adjacent the slots 96-96and a groove 100 into which there is adapted to be seated a snap springring `102, of l Wire or: the like.' A thin steel washer 103, relativelyclosely embraces :the sleeve67 and is retained ybythe snap, orspringring'102. A washer 104 Vof bakelizedffabrcor bakelizedbre-or the like isinterposed between the steel `washer 103 and the hub 66 .of'the This.washer 104. fitsirelatively closely yon the lcylindricalY .part of lthesleeve 67. A ring 105 `of similar insulationembraces the sleeve-67 andlies #within the-hub 66. Upon the opposite side of the hub fromthering104 a washer of similar insulation 106 embraces thesleeve 105. A steelwasher-107 backs, the in 'sulating washer 106 and' is'- interposedbetween the said insulating washer 106r` and, the shoulder 99. Ifdesired, a" thin steel *washer 108 l'may' be interposed :between thelinsulating washer .104

V:and the hub 66 to `,reduce wear.

pThe-hub 66 iis, by means of these washers and thesleeve 105, insulated.from the, shifter Vssleevell.` I I rshifts the sleeve .87 .and 'therebythebrushes p63 .andthe short circuiting ring. 62, is shown more 1indetail in-Figures. 4, 5 and 6.

mechanism comprises the .collar li281" which is;flxerl` uponpthe reducedportion :23 of the shaft 19. as xbyfmeans of .fa pair of set. screwsl09-arrangedzat suitable .parts of the periphery 'of the collar, forexample, at 90 to eachother.

This icollar supports. a transverse` sheet metal.

plate .1.10 `which is secured .to the said, ycollar by riveting,:welding'or the like AIn the `form .shown the collar :28is-provided withare'duced -neck1112having a shoulder at one side and having `the .neckriveted over aty the` opposite.

side .so asitogrip the plate llfrmly.,

'The plate 110"is generally rectangular in outjj,l 80 The inertia, .or.centrifugal/mechanism Which .line :but yit has the margins at oppositesidesv l bent up at right anglesv to the body ofthe plate asshowny at113 in Figures 4 and "5to provide flanges, `whichfianges arecut out. toprovidethe pivot ears 11'4,four in number,at each en dfof the flange113. Between each ypair rof ears formed on .the vflange 113 there .is.provided *a guard or retaining ear 1-15 whichV is curved aroundthecentral part of the corresponding f tension spring 116 to prevent thecentral part of such spring from ilyingout radially under centrifugalstress. I The lshiftingpins 97-97 are riveted,V or otherwise fixed-attheir opposite ends in companion levers '.117 which are formed asU-shaped stampings, the joining bar, or bottom ofthe U by .which pairsof levers 117 are integrally joined, being lplainly shown in elevation'in1,15v

rFigure .5. If it is desired' to increase the weight of the bar ll8.anadditional 'flat bar such as that lshown at 119 in Figure`2" may beriveted to the bar 118.

The levers 117 are in effect bell ycrank levers comprising the shifterarm 120 and the inertia .arm.122, theinertia arrnl in each ycase havingthe bar 118 joined thereto. The pivot or fulcrumI on .the pin 98 isdisposed radially beyond the arms 120 `and 122 and it may be seen,therefore, that the,

inertia weight 118 is leastY effective before thebell crank levers swingabout their pivots 98 andare of substantiallymaximum effectivenessafter'the inertia weightshavecaused the levers to move and to shifttheshifter sleeve 67 Ato the right asjo` lindrical vbody of-the ring 123bears edgewiseagainst the plate 110 radially 'beyond the riveted.neck*112. jBy means of vthe buffer ring'123'a suitable stop for theshiftersleeve 67 is provided andalso the collar 28 is accurately spacedwith respect to the'shoulder 93 on the shaft 19. Afelt'.

washer.; 125 .is preferably. interposed between the .bufferr'ring'123.and the endof the shifting .sleeve 67. Preferably an: anti-frictionlwasherof bakelized Lfebr-ic or the like islocatedv at 126- betweentheendVV of the-)collar 29and the be'aringl bushing to `the right asviewed in Figures 1 and 2.

17. Likewise, one or more lwashers may be interposed at 127 between theshoulder 129 atthe opposite end of shaft 19 and the bearing bushing .18of the bearing box 16. a

The bell crank levers 117, which arelshownin -elevation in Figure 1 areprovidedv with short "arms 129 lying, when the parts are in the posi- Yi tion shown in Figures 1 and 2,'radially. 'beyond ends of the said pins130 are provided with cir- I cumferential grooves `and the springs 116are provided with eyes which hook over the ends Tof the pins 130` andrest in the said grooves. The pins 130 are nurledy or scored andpressedinto the arms 129 so thatthey are thereby retained againstVmovement by the locking action ofthe nuris132 with'the bore of `theopening through the corresponding arm 129.`

The operation of the brush shifting and short oircuiting mechanism is asfollows: With the parts as shown in Figurel or 2 the springs 116 bringthe pins 13,0 inwardly until they engage the pivot ears 114. This holdsthe inertia weight `such as 118 in their innermost position. The

shifter arms 120` of the bell crank levers 117 have, through theirconnected shifter pins 97 and the slot 96, shifted the sleeve 67 tosubstantially the limit of movement inwardlyV or At this time the shortcircuiting band 62 is housed entirely within the commutator frame awayfrom the commutator segments. At the same time the brush holder frameiscarried towards the Acornrnutator so that the brushes 63 engage theradial'face ofthe commutator. The springs 116, operatingl through theleverage system, apply suflcient pressure to the brush holder frames toovercome the relatively `light tension of the brush follower springs"l2,` so that the brushes 63 are applied underwa' light, but sufficient`spring pressure against the radial'face's of the commutator bars.

If now the stator 1 is energized by connecting to a source of suitablesingle phase current, the leads for which maybe led to the statorwindings through the insulating sleeve 133, therotor windings areenergized. The present motor is provided with two pairs of poles and thebrushes are arranged to selectively short circuit the coils of the rotorthrough the commutator to cause the motor to start up as a repulsiontype motor.` As is well known, sufficient torque may be developed tostart under fairly heavy load.

sleeve 67 is quickly thrown, or snapped to the collar 28 has upon Vthereduced portion 23` of the shaft 19, this being secured, primarily, bythe setl screws 109. The grooves-96in which `rosarino the shifting pins97 are arranged to play, are straight cross grooves and hence anytendency to cause rotation between the shifter sleeve 67 .andthe shaft19 will be unable to effect the same, since the grooves96 do not extendcompletely around Ythe shifter sleeve 67. Also, the friction ,betweenthe short circuiting band 62, the groove 94 onthc one hand and therecess 50 on the other, tends to prevent such rotation.

j The brush holder frame 61 is held against rotation by the guiding pins79 which are fixed on the rocker plate 36.

As the shifter levers operate to carry the shifter sleeve 67 to theleft, the shifter sleeve first carries the short-circuiting band acrossthe plate of insulation into engagement with the commutator segments 55,short circuiting the windings of the rotor 2 and causing the mo tortocontinue to operate as an induction motor, and thereafter the brushes 63are lifted or moved out of engagement withthe commutator. This movementof the short circuiting band to `short circuiting position first isaccomplished by positioning of the short circuiting band for movementwith the initial movement of the shifter sleeve 67 whereas the followerlevers 70 tendto maintain the brushes 63 in engagement with thecommutator at least momentarily or during the initial movement of thesleeve 67. The distance which the spring actuated brush follower levers70 can follow the brushes is limited by the engagement of said levers 70with the sides ofthe brush holder sockets, so that the brusheswill beremoved from engagement with the commutator segments and at the sametime wear `between thev brushes and commutator is reduced.

It will be observed that the brush holder frame `will assume a positionon the guiding pins 79 where minimum friction with respect to the movingsleeve 67 occurs.

Since the guarding ears 115 are located at the central parts of the'springs they do not interfere with theeifective and equal operation ofthe two ends of the springs.

In Figure 2 I have shown a modified form of commutator. -In thisconstruction the commutator bars are recessed at their backs to receivelan insulating ring 135. This ring has a series of counterboredholes forreceiving mounting rivets. Thefdo'ublevended rivets 136 have collars attheir central portion and one end of the rivet, in each" case, is firstspun or riveted lthrough the holein the ring 135 and then the commutatorbars are mounted on said ring in spaced relationandheld thereto as bymeans of the riveted pins 137. The insulating plate 66 is thenlaid uponthe back of Ythe ring 135 `and the cylindrical inner edges of thecommutator bars and the inner ends of the rivets 136 are spun or rivetedtothe flange 48 of the commutator body or frame 47. .i

VThis construction is optional. The specic form` of the commutator islnot involved in the present invention so long as it conforms to therequirements of the brush lifting and short ciry cuiting mechanismheretofore described. n

I do not intend to be limited to the details shown and described, exceptas they are recited in the appended claims.

I claim:

1. In a mechanism of the class described, the combination with a motorshaft and end frame of a plate mounted on the end frame and adapted forangular adjustment relative thereto, guiding pins mounted on the plate,a brush holder frame sleeved on said pins for free end wise movement-onsaid pins, a sleeve endwise shiftable on the shaft, a frame xed cn theshaft, shifter levers pivoted on said latter frame and having operatinorarms coupled to said sleeve and inertia arms and tensionsprings lying onopposite sides of the shaft connecting said levers to hold the inertiaarms inwardly when the shaft is at rest, said sleeve and said gorushholder frame being coupled together for endwise motion but beingrotatable relative to each other.

2. In combination, a shaft, a motor frame member, a centrifugalmechanism comprising levers having inertia arms mounted on the shaft, ashifting sleeve on the shaft coupled to said levers,k a brush framemounted on the sleeve for endwise motion therewith but free for relativerotation therebetween, and a non-rotatable guide disposed radiallyoutside the centrifugal mechanism,` said brush frame being slidablyguided on said guide and brush means carried by said brush frame andmovable into and out of engagement with the commutator.

3. A guide frame for centrifugally operated brush holder framescomprising a plate having a central opening adapted to embrace a guidinghub and having an arcuate slot concentric with said opening, offsetportions disposed about the marginscf the plate and having openingstherethrough, and shouldered pins riveted in said openings, Asaid pinsextending parallel to the axis of said central opening and attacheddirectly to said plate.`

e. In combination, a motor end frame having a bearing providing a huband having a fiat f j end wall, a guide frame comprising a hat platehaving a central opening piloted on said hub, an arcuate slot adjacentkthe lmargin of the plate, a clamping bolt passing through said slot andthrough said flat end wall, a plurality of oilset earson the margin ofthe vplate and guide pins secured to said ears and extending parallel tothe axis of said central opening, said guide pins being carried by saidplate independently of the end wall of the motor frame and independentlyof said clamping bolt.

5. In combination, a motor end frame having a bearing providing a huband having a flat end wall, a guide frame comprising a 'fiat platehaving a central opening piloted on'said hub, an arcuate slot adjacentthe margin of the plate, a clampirnT bolt passing through said slot-andthrough said flat end Wall, a plurality of offset ears on the margin ofthe plate, guide pins secured to said ears and extending parallel to vthe axis of said central opening, a brush holdarcuate slot adjacent themargin of the plate, a clamping bolt passing through saidv slot andthrough said flat end Wall, a plurality of offset ears on the margin ofthe plate, guide pins secured to saidears and extending parallel to theaxis of said central opening, a brushholder frame sleeved on said pinsand free to move en wise thereupon, and brushes carried by said holder,the slot permitting sufiicient rocking adiustment to locate the brushesso as to produce rotation of the cooperating armature in eitherdirection, there being sleeves of insulation fiiredly mounted in saidbrush holder frame and freely slidable on said pins, and inertia Weightmechanism adapted to operate the brush holder frame out insulatedtherefrom.

'l'. In combination in a motor, a frame having end plates providingbearings,l one of ksaid bearings providing a piloting hub, a shaftmounted in the bearings, a commutator on the shaft comprising a basehaving a hub which is secured on the shaft, said base having a concenvtric cylindrical recess, metallic segments mounted in insulated relationon the base, said segments having radial faces adapted to be engaged bybrushes and having a cylindrical inner face substantially registeringwith the surface of the recess, a rocker plate having an opening pilotedon said piloting hub and adjustably clamped to the adjacent end plate,guiding rods mounted atene end on said rocker plate and extendingparallel to the axis of the shaft,'a brush holder frame sleeved on saidrods, brushes for cooperation withy the vradial faces of the commutatorsegments carried by said latter frame, a shifter sleeve slidably mountedon said shaft Vand having one end extended into said cylindrical recess,said end of the sleeve having a groove, a spring band mounted in saidgroove and adapted when the sleeve is shifted to be brought into Contactwith the cylindrical faces of saidsegments to short circuit the same, acentrifugal mechanism carried on said shaft and confined radially withinsaid guiding rods, said latter mechanism comprising levers carryinginertia weights and having operating connections With said shiftersleeve, said brush holder frame embracing said sleeve and there beingshoulders on the sleeve on each. side of the shifter frame. Y

8. In combination, a shaft, a collar onthe shaft fixed thereto, atransverse plate mounted on said collar, said plate having pivot earsdisposed in pairs on opposite sides. of the shaft, said ears beingdisposed at right angles to the body of the plate and pairs thereofhaving pivot holes in alignment with each other, bell crank leversformed of 'l1-shaped stampings having pivot holes disposed between pairsof ears, pivot pins extending through said aligned holes in the ears andin the bell cranks, the bottom of the U of each lever stamping providingan inertia Weight, both arms of each bell crank lever extending inwardlyfrom the pivots in said ears, the free ends of the U-shaped stampingsbeing joined by transverse pins, said bell crank levers naving armsdisposed beyond said pivot openings, transverse pins extending betweenthe arms, said pins at their ends extending out beyond the pivot ears,and a pair of tension springs connecting the outer ends of said lastnamed pins, a sleeve on the shaft, said sleeve being grooved to receivethe nrst named transverse pins.

9. In combination, a shaft, a collar on the shaft fixed thereto, atransverse plate mounted on said collar, said plate having pivot earsdisposed in pairs on opposite sides of the shaft, said ears beingdisposed at right angles to the body of the plate and pairs thereofhaving pivot holes in alignment with each other, bell crank leversformed of U-shaped stampings having pivot holes disposed between pairsof ears, pivot pins extending through said aligned holes in the ears andin the bell cranks, the bottom of the U of each lever stamping providingan inertia weight, both arms of each bell crank lever extending inwardlyfrom the pivots in said ears, the free ends of the U-shaped stampingsbeing joined by transverse pins, said bell crank levers having armsdisposed beyond said pivot openings, transverse pins extending betweenthe arms, said pins at their ends extending out beyond the pivot ears,and a pair of tension springs connecting the outer ends of said lastnamed pins, a sleeve on the shaft, said sleeve being grooved to receivethe first named transverse pins and switching means carried by said lastnamed sleeve.

10. In combination, a shaft, a collar on the shaft fixed thereto, atransverse plate mounted on said collar, said plate having pivot earsdisposed in pairs on opposite sides of the shaft, said ears beingdisposed at right angles to the body of the plate and pairs thereofhaving pivot holes in alignment with each other, bell crank leversformed of U-shaped stampings having pivot holes disposed between pairsof cars, pivot pins extending through said yaligned holes in the earsand in the bell cranks, the bottom of the U of each lever stampingproviding an inertia weight, both arms of each bell crank leverextending inwardly from the pivots in said cars, the free ends of theU-shaped stampings being joined by transverse pins, said bell cranklevers having arms disposed beyond said pivot openings, transverse pinsextending between the arms, said pins at their ends extending out beyondthe pivot ears, and a pair Aof tension springs connecting the outer endsof said last named pins, a sleeve on the shaft, said sleeve beinggrooved to receive the first named transverse pins, said transverseplate having ears extending outside the central parts of said springs torestrain the springs from being extended radially by centrifugal force.

11. In combination, a shaft, a collar fixed on the shaft, a transversegenerally rectangular plate fixed to the collar, a shifter sleevemounted on the shaft, said plate having pivot ears bent up along twoopposite margins, said ears being apertured, pivot pins extendingthrough the apertures of the ears and lying parallel to each other onopposite sides of the shaft, four bell crank levers mounted cn saidpivot pins inside said ears and comprising inertia arms and operatingarms, said levers having their pivotal portions disposed radiallyoutermost so that the arms extend diagonally inwardly generally towardthe shaft, the operating arms of each pair being joined by a transverseshifter pin, the inertia arms of each pair being connected together by atransverse inertia member, said shifter sleeve being grooved to receivethe shifter pins, said levers having outward extensions and springanchor pins extending through said extensions and projecting across theedges of the ears and serving to limit the angular position of saidlevers, and tension springs connected to the ends of said latter pinsfor holding the inertia arms inwardly, and a brush holder frame guidedlongitudinally of the shaft and coupled to said shifter sleeve.

l2. In combination in a motor, a motor frame having end framescomprising bearings, a shaft extending through said bearings, one ofsaid end frames having a flat internal clamping face and the bearingthereof having a piloting boss, a rocker guide plate having an openingpiloted on said boss, and having an arcuate slot for angular adjustmentabout said boss, clamping means extending through said slot for clampingthe guide plate against the clamping face of said end frame, guide rodsfixed to said rocker plate, a brush holder sleeved on said rods, saidshaft having a shoulder adjacent said bearing of said one end frame, acollar on said shaft, a transverse pivot plate secured to the end ofsaid collar remote from said one bearing, a hollow spacer disposedbetween the shoulder on the shaft and said pivot plate, said pivot platehaving integral pivot ears extending in parallel planes on each side ofthe shaft, U- shaped stampings providing leaded bell crank levers attheir ends extending in planes parallel to the pivot ears and thepivotal portions of connected bell crank levers, shifter pins connectingthe free ends of the bell crank levers, shifter sleeve guided on theshaft and being grooved at opposite sides to receive the shifter pins,said pins preventing rotation between the sleeve and the shaft, coilsprings lying outside the pivot ears and parallel thereto connecting theadjacent ends of said U-shaped stampings, said transverse piate havingfingers extending around the outside of said springs along their centralportions to prevent radially outward movement thereof due to centrifugalforce.

13. In combination in a motor, a motor frame having end framescomprising bearings, a shaft extending through said bearings, one ofsaid end frames having flat internal clamping face and the bearingthereof having a piloting boss, a rocker guide plate having an openingpiloted on said boss and having an arcuate slot for angular adjustmentabout said boss, clamping means extending through said slot for clamptheguide plate against the clamping face of said end frame, guide rodsfixed to said rocker plate, a brush holder sleeved on said rods, saidshaft having a shoulder adjacent said bearing of said one end frame, acollar on said shaft, a transverse pivot plate secured to the end ofsaid collar remote from said one bearing, a hollow spacer disposedbetween the shoulder on the shaft and said pivot plate, said pivot platehaving integral pivot ears extending in parallel planes on each side ofthe shaft U-shaped stampings providing loaded bell crank levers at theirends extending in planes parallel to the pivot ears and the pivotalportions of connected bell crank levers, shifter pins connecting thefree ends of the bell crank levers, a shifter sleeve guided on the shaftand being grooved at opposite sides to receive the shifter pins, saidpins preventing rotation between the sleeve and the shaft, coil springslying outside the pivot ears and parallel thereto connecting theadjacent ends of said U-shaped stampings, said transverse plate havingfingers extending around the outside of said springs along their centralportions to prevent radially outward movement thereof due to centrifugalforce, a commutator having segments provided with a radial face and aninternal cylindrical face, said shifter sleeve having a groove, and acoil spring of toroidal form disposed in said latter' groove and beingadapted to engage the cylindrical surface of said segments when theShiite sleeve is shifted by said shifter pins.

14. In combination in a motor, a motor frame having end framescomprising bearings, a shaft extending through said bearings, one ofsaid end frames having a flat internal clamping face and the bearingthereof a piloting boss, a rocker guide plate having an opening4piloted. on said boss and having an arcuate slot for angular'adjustment about said boss, clamping means extending through said slotfor clamping the guide plate against the clamping face of said endframe, guide rods fixed to said rocker plate, a brush holder sleeved onsaid rods, said shaft having a shoulder adjacent said bearing of saidoney end frame, a collar on said shaft, a transverse pivot plate securedto the end of said collar remote from said one bearing, a hollow spacerdisposed between the shoulder on the shaft and said pivot plate, saidpivot plate having integral pivot ears extending in springs lyingoutside the pivot ears and parallel thereto and connecting said U-shapedstamp-A ings, saidgtransverse plate having nii-gers extending around theoutside of said springs along their central portions to prevent saidsprings being extendedby their own centrifugal force,

Va commutator having segments prov'ded with.

a radial face and an internalcylindrical face, said shifter sleevehaving a groove, and a coil spring band disposed in said latter grooveand being adapted to engage the cylindrical surfaces of said segmentswhen the shifter sleeve is shifted by said shifter pins, said brushholder having a central hub portion provided with an aperture passingover said shifter sleeve, said shifter sleeve having a shoulder lying onone side of the hub portion of the brush holder and a groove upon theother side thereof, and a snap ring in the groove for holding theshifter sleeve and the brush holder together for endwise motion butpermitting rotative motion.`

15. In Vcombination with a cominutator having segments provided withradial faces and internal cylindrical faces of a short circuiting meanscomprising a sleeve having a relatively wide shallow groove and a bandshaped coil spring the median parts of the coils of which are offsettoward each other, leaving enlarged portions at the end of each coilwhich are relatively `ireely expansible and conipressible radially oithe sleeve to make good short--circuiting contact with the cylindricalsurface of said segments, a motor shaft, said sleeve having a secondgroove and centrifugal means including a shifting lever having a pinlying in a direction erally across the axis of the motor shaft andengaging in said second groove. l

16. In combination, a brush Supporting frame comprising a central hubportion having a cenn tral bore and integral brush holders having oblongbores therethrough parallel to the central bore, ears extendingoutwardly from said brush holders, brush follower levers pivoted betweensaid ears, springs disposed about the pivots of said levers for urgingthe ends of the levers toward the sockets, mounting sleeves having boresthe axes of which are parallel tothe axis of the central bore and uponopposite sides of the saine, said sleeves being attached to the hub bywebs joining adjacent brush holders.

17. In combination, a brush supporting frame comprising an apertured hubportion and peripherally disposed brush holding sockets open at bothends, integral guiding sleeves on the hub portion, stationary guide rodsextending through said sleeves and a shifter sleeve having shoulders onopposite sides or" the hub for shifting the brush supporting frame onsaid guide rods.

18. In combination, a rotatable shaft having a reduced portion and amain portion with a shoulder between them, a collar fixed upon thereduced portion, a transverse frame plate secured upon one end or" thecollar, shifter levers having inertia arms, springs `for said levers,said levers being pivoted on said frame plate, a shifter sleeve slidableon the main portion of said shaft, shifter connecting `the levers andthe sleeve, aV buner collar of a diameter greater than the diameter ofthe main portion of the shaft lying between the said shoulder and saidframe plate and adapted to be engaged by the sleeve when the shifterlevers are actuated by the inertia arms.

19. A centrifugal switching device comprising a rotatable shaft, astationary guide parallel to the shaft, a frame non-rotatably guidedalong said guide, said frame carrying an electric contact, collar on theshaft, a transverse plate on said collar, said plate having pivot earsdisposed in parallel planes upon opposite sides of the shaft, U-shapedstampings comprising each a transverse joining portion providing aninertia meinben'and bell crank levers disposed in parallel planes tosaid pivot ears, pivot pins in said pivot ears extending parallel tosaid transverse plate and passing through the said bell crank levers,said cell crank levers having inertia arms joined by lsaid inertiamember and free arms having shifter pins, and a yshifter sleeve forshifting said frame, said sleeve being disposedcn said shaft and havinggrooves for. receiving said shifter pins.

20. A centrifugal switching device comprising a rotatable shaft, atransverse plate mounted nonrotatably on the shaft, said plate havingintegral pivot ears at its opposite margins disposed in parallel theshaft, a pair of Ushaped stampings each comprising a transverse joiningportion providing an inertia member, and bell crank levers disposed inparallel planes adjacent the pivot ears, pivot pins extending throughthe ears and the levers, said pins lying substantially in a common planeparallel to said plate, said levers having inertia arms joined by saidinertia memand :free shifter arms provided with shifter pins, a shiftersleeve on the shaft, said sleeve being grooved to receive said pins,Vand electric switching means actuated by shifting of said shiftersleeve.

CLARENCE RINGWALD.

lanes upon opposite sides of Y

